Rheostat



(No Model.)

E. W. RICE, J1".

- RHEOSTAT. No. 888,918. Patented June 5, 1888.

Figi .MK figg.

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il. VLBUR RICE, JR., OF LYNN, B'ASSAGHUSETTS.

t? H EOSTAT.

LSPECIECATION forming part of Letters Patent No. 383,913, dated Enne 5,1888.

Application lleil February -l, 18.98. Serial No. 2672.953. (No model.)

To @ZZ whom, it may concern,.-

Beit known that i, E. Vitrina Rien, Jr., a citizen of the United States,and a resident of Lynn, in the county of iilssex and State ofMassachnsetts,havc invented a certain new and useful ithcostat orResistance for Electric Circuits, ol` which the following isaspeciiication.

My present invention relates to improvements in the construction ofrheostats or resistances for electric circuits, whereby I obtaincheapness ofconstrnction, neatncss in design, ease and certainty ol`operation, and extreme simplicity.

My invention consists in a novel construction and arrangement oi theparts of the apparatus,which will behereinatter fully described,reference being had to the accompanying drawings, in enrich-- Figure lis a plan view partly ofthe internal structure of my invention andpartly of the external structure. Fig. 2 is a cross-section, certainparts being shown in side view. Fig. 3 is an end view ofthe apparatus.Figs. t and illustrate forms of conductor that may be used in theapparatr...

In the construction of rheostats or resistanccs for electric currents ofconsiderable volume it is very desirable that the parts be so arrangedas to at'tord rapid and constant radiation of the heat produced by thecurrents to the outer air; that these parts be easy of access, so as toavoid diiiiculty in the event of accident to the apparatus, and that theliability of the rheostat to short circuits77 be reduced to minimum.

The object of my invention is to secure these features of construction,together with cheapness and simplicity in the arrangement of the parts.

In Fig. LTV indicates a base plate or board, Twhich may be of wood orany other desired material, preferably an 'insulating material.Supported above this plate in any desired way is a second plate ortable, formed, preferably, in two parts, I B, as will be presentlydescribed, from which plate or table project inwardly, or at rightangles therefrom, and into the free air-space between the base andtable, two sets of pins or studs, P L, arranged, preferably, in circularor curved lines, in order to secure compactness.

rPhe pins or studs P may be of any desired material, but in the presentease are supposed to be of iron and project from the plate or portion ofplate i, to which they are secured or attached by cast-ing in one pieceor by other means.

The plate i and its studs or pins might be of insulating material; butfor the sake of simplicity and cheapness I prefer to make them of iron.The plate I is in the form ot' an annulus or disk open at its center toform a space through which the pins L may project. The latter pins areof conducting material, and are attached to or project from aseries ofcontactblocks, C, which are arranged in a circle upon a plate or board,B, that is preferably made ol" insulating material, and is suitablysecured to the part I.

The blocks C are attached to the board or plate B in any desired way,and the pi nsL may be cast in one piece with said blocks. The pins passthrough periorationsin the block or plate B.

Upon the plate B is mounted a pin or stud upon which the contact arm orswitch A swings by means of a thumb-piece or handle, H. The arm orswitch A is held in iirm coutact with the switch -blocks by means ot aspring, S, and electrical connection with the switch-arm is made throughthe pin or stud upon which itis mounted, said pin or stud being properlyconnected in any ordinary way with one of the binding-posts K of theapparatus. One end of the switch-arm A is provided with aninsulating-face, or is made of insulating material, as indicated in Fig.2, so that it shall not make electrical connection with thecontact-blocks C.

The Various pins l) L extend to within a short distance ofthe base-boardXV, but do not touch the same.

The opening at the center of the disk or annulus I should besuliiciently large to leave a considerable space between its tges andthe pins L and the dish I, when thelatter is made of conductingmaterial. The pins are arranged,preferably,at uniform distances apart,and when the resistance consists of a continuous circuit, the length ofwhich is varied in order to vary the effective resistance, it isdesirable that the inner set ot pins, L, should loc placed on radiallines passing between the outer set of pins, P.

That contact-block C, which is connected with the pin L from which theelectric-resistance conductor starts,is electrically connected with thebinding-post K in obvious manner. The strips or pieces of conductorwhich form the sections of the variable resistance are indicated at R.In the present instance, wherero in I have illustrated the applicationto the frame of a sectional resistance whose length is varied, eachsection of said resistance is represented by lines which, starting fromone of the pins L, pass to one of the outer pins, P,

i5 and thence back to the next pin L of the inner set. Ihe sections ofresistance,supportcd, as indicated, between the pins of the two sets andbridging the space between such sets, maybe secured on the pins in anydesired 2o manner.

A preferable manner ofsupporting and arranging the resistance,when thesame is to consist of a conductor of variablelength, is as follows: Awire strip or other continuous form of German silver or other suitablematerial is fastened at one of its ends so as to be electricallyconnected with that pin L of the series of conducting-pins which isconnected to or projects from any initial contact-plate C 3o that iselectrically connected with the bindingpost K. The wire strip or otherform is then passed around the nearest pin P, Fig. 1, of the outer set,and if said pin P is of conducting material itis carefully insulatedtherefrom by 3 5 insulation indicated by the heavy circular black line.The conductor or wire is then earried to the next pin L of the inner setand electrically connected with it by simply allowing it to rest in freeconnection with the 4o same, and the process is repeated in the mannerindicated to any desired extent. The winding is continued backward andforward from the pins L to the pins P, a good electric connection beingmade with the pins L, and a thorough avoidance of contact at the pins Pbeing observed until the circle or the portion of the circle which it isdesired to use is completed. When the apparatus is thus arranged, itwill be obvious that by moving the arm A 5o to any plate G, any desiredresistance can be thrown into circuit, as the circuit will then becomplete from the binding-post K, through whatever resistance may havebeen thrown into circuit between that contact C and the ter minalcontact C, connected with the bindingpost K.

It will be observed that by this construction almost the entire spacebetween the base W and the top plate or support is left exposed,

6o so that air may freely circulate around the resistance, therebylargely preventing the bad effects which might arise from theaccumulation of heat. y

It will be seen, also, that from the conven- 65 ent size and small depthof the apparatus it may very readily be -placed upon a wall as a cutoutbox is placed, so that the switch-arm for cutting in and ont resistancemay be easily reached by the hand.

In the construction of rheostats for currents of moderate strengthl andof comparatively high potential the resistance-windings may becorrugated between the supporting lugs or pins L L and P P, or they maybe of spiral wire instead of straight, so that a greater' length ofconductor or resistance in the path of current ymay be obtained betweenany two of the contact-plates C C. These modifications are indicated inFigs. 4 and 5.

The mechanical construction of my resist? ance-frame is such that, aswill be obvious, it may be readily employed for other arrangements ofthe conductor or conductors forming the electric resistance, as will bewell understood by electricians.

What I claim as my invention isl. In an electric resistance-frame, thecombination of a series of conducting pins or studs projecting inwardfrom a suitable support and east in one piece with eontactplates G,arranged upon the outer face of the support, a second set arrangedparallel with t-he first, and electricresistanee strips or piecessupported by said studs and bridging the space between the sets.

2. In an electric resistance-frame,the combination of a series ofconducting pins or studs projecting inwardly from a suitably-supportedplate, a second set of pins arranged parallel with the first, butinsulated therefrom, a continuous resistance strip or wire strung uponthe two sets of studs and bridging the space between the two sets, and aseries of switch contacts eastin one piece with the conducting pins andarranged upon the outer face of the support, as and for the purposedescribed.

3. In a rheostat, the combination, with two sets of pinsor studsarranged in circles one within the other, of a set of contacts connectedwith the pins of one set, a contact-arm or circuit-closer adapted tomove over the same, and an electric resistance wound upon the two setsof pins and in electric connection with the pins connected with thecontacts, as and for the purpose described.

4. In an electric resistance-frame, the combination of two sets of pinsor studs projecting from the same side of a suitable support andarranged in circles, one set of pins being of conducting material andelectrically disconnected from the other set excepting by the conductorforming the electric resistance, and a set of contacts connected withthe conducting pins or studs.

5. The combination, with a baseplate, of a disk-plate or annnlussupported thereon and having a series of pins or studs projecting fromits under surface toward the base-plate, a second plate of insulatingmaterial carrying a series of conducting pins or studs, also projectingtoward the base-plate, a se'ries of con- ICO I-IO

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tacts mounted on the insulating-plate and elecl trically connected withthe conducting pins or studs, and an electric resistance supportedbetween the pins of the two series, as and for the purpose described.

6. An electric resistance-traine consisting, essentially, of abaseplate, a superposed supporting table or plate separated from thefirst by a free air-space, two sets of pins projecting into said spaceat right angles to the base, one set being` of conducting material, aseries of contacts mounted on the face of the table or outer plate andseverally connected with the pins ot conducting material, and anelectric resistance supported by the two sets of pins and lnidging thespace between the two sots.

7. In an electricresislance-fraxne, aseries of eontactbloclrs, C,mounted on an insulating board or plate, B, and having pins or studs Lformed integral with 'them and projecting through said board into thespace between the latter and tlie base-plate, as and for the purposedescribed.

8. In an electric resistance-frame, the con1- bination of a baseplate, asuperposed disk or plate, l, having a series of pins projecting inwardfrom it and cast integral with it, aboard or plate of insulatingmaterial, B, carrying contact blocks and studs L of conducting materialprojecting inward toward the baseboard, and a continuous electricConductor wound to and fro upon the two sets of pins and across thespace between the sets, as and for the purpose described.

9. The combination, with a suitable base board, ot' a disk or aunulus,of iron, having a series of pins, P, projecting downward from the same,a plate ot' insulating material snpported over an opening in the centerof the plate I and carrying a series of conducting pins or studsprojecting inward from it and electrically connected with blocks orstuds mounted on the base ofthe plate, and an electric conductor strungacross the space between the two sets of pins, as and for the purposedescribed.

WILBUR DICE, JR.

Witnesses:

Gris K. STUART, J. XV. GrBnoNEY.

